<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.w3.org/1999/xhtml">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<form action="/uu" method="post">
        <input type="hidden" name="id" th:value="${uu!=null}?${uu.id}">
    姓名<input type="text" name="name" th:value="${uu!=null}?${uu.name}">
    性别<input type="text" name="xb" th:value="${uu!=null}?${uu.xb}">
    年龄<input type="text" name="age" th:value="${uu!=null}?${uu.age}">
    <input type="submit" value="提交">
</form>

</body>
</html>